Rising global temperatures portend uncertain future

Global temperatures continue on a rising trend, according to
scientists at NOAA’s National Climatic
Data Center in Asheville, N.C. The implications of this trend
are quite serious, and I’ll discuss some new studies after
reviewing the temperature data for 2010.

The worldwide average surface temperature for the past year tied
with 2005 as the warmest year on record, a record that goes back to
1880. And the year 2010 was the 34th consecutive year in which
temperatures were above the 20th century average, according to a
preliminary analysis by NCDC.

The decade of 2001–2010 was the warmest ever recorded for the
surface of the Earth during that 130-year time period. It was some
1.01 degree F. above the 20th century average. The previous record
for a full decade was also recent, 1991-2000, when the temperature
was .65 degrees F. above the average.

The years 2005 and 2010 were 1.12 degrees F. above the century
average of 57.0 degrees F. when combining the land and ocean
surface temperatures. The year 1998 is the third-warmest on record,
measured at 1.08 degrees F. above the century average.

When looking at the Northern Hemisphere alone, 2010 was the
warmest year on record for combined land and ocean surface
temperatures. But in the Southern Hemisphere, temperatures were the
sixth warmest on record.

For land surface alone, 2010 and 2005 tied for the second
warmest on record, at 1.73 F. above the average. The warmest year
on land was 2007, when the average temperature was 1.73 degrees F.
above the century average.

Global ocean surface temperature for 2010 tied with 2005 as the
third warmest on record, at .88 degrees F. above the century
average.

Evidence shows an ongoing warming trend, and climatologists are
fairly convinced that the temperature rise is related to an
increase in greenhouse gases in the Earth’s atmosphere, including
carbon dioxide (CO2), methane (CH4) and nitrous oxide (NO2).

“Atmospheric concentrations of CO2 (379 ppm) and CH4 (1774 ppb)
in 2005 exceed by far the natural range over the last 650,000
years. Global increases in CO2 concentrations are due primarily to
fossil fuel use, with land-use change providing another significant
but smaller contribution.

“It is very likely that the observed increase in CH4
concentration is predominantly due to agriculture and fossil fuel
use. CH4 growth rates have declined since the early 1990s,
consistent with total emissions (sum of anthropogenic and natural
sources) being nearly constant during this period. The increase in
NO2 concentration is primarily due to agriculture.

“There is very high confidence that the net effect of human
activities since 1750 has been one of warming. Most of the observed
increase in global average temperatures since the mid-20th century
is very likely due to the observed increase in anthropogenic GHG
concentrations. It is likely that there has been significant
anthropogenic warming over the past 50 years averaged over each
continent (except Antarctica).

“During the past 50 years, the sum of solar and volcanic
forcings would likely have produced cooling. Observed patterns of
warming and their changes are simulated only by models that include
anthropogenic forcings. Difficulties remain in simulating and
attributing observed temperature changes at smaller than
continental scales.”

One of the factors that needs to be resolved with more precision
is how fluctuations in solar energy reaching the Earth affect
global temperatures. New satellite data have been examined, and new
satellites will be going up soon to help resolve discrepancies in
estimates of total solar irradiation.

In an announcement last week, the American
Geophysical Union said the new solar data should help
researchers better calculate the heat contribution from the sun
going back 32 years.

Judith Lean of the Naval Research Laboratory in Washington,
D.C., made this comment:

“We are eager to see how this lower irradiance value affects
global climate models, which use various parameters to reproduce
current climate: incoming solar radiation is a decisive factor. An
improved and extended solar data record will make it easier for us
to understand how fluctuations in the sun’s energy output over time
affect temperatures, and how Earth’s climate responds to radiative
forcing.”

Meanwhile, ongoing research continues to raise alarms about
greenhouse gas emissions from human sources. A study by Jeffrey
Kiehl of the
National Center for Atmospheric Research suggests that if
carbon dioxide emissions continue at their current rate through the
end of this century, concentrations would reach levels that last
existed 30 million to 100 million years ago, when global
temperatures averaged about 29 degrees F. higher than in
pre-industrial times.

Elevated levels of carbon dioxide would remain even if emissions
were eliminated, and today’s rising temperature trend could be
expected to continue for centuries. I’m not sure how much to rely
on this one report, but makes you stop and think.

Here’s how Kiehl sees it:

“If we don’t start seriously working toward a reduction of
carbon emissions, we are putting our planet on a trajectory that
the human species has never experienced. We will have committed
human civilization to living in a different world for multiple
generations.”

One thought on “Rising global temperatures portend uncertain future”

If you haven’t heard, the $424-million satellite I discussed in this article failed to make orbit last week and is probably resting on the bottom of the Pacific Ocean.

The accident has left NASA rocket scientists “devastated,” according to an article by Lauren Morello in the New York Times. The satellite, name “Glory,” was designed to increase the overall knowledge of Earth’s energy balance, as described on NASA’s page dedicated to the program.